Radio frequency identification (RFID) “tags” are used in a variety of commercial and government applications to provide the means to securely identify an object to which a tag is affixed. Briefly and as is known in the art, RFID tags are powerless passive devices that are “activated” in the presence of a radio frequency (RF) electromagnetic wave. An activated RFID tag resonates to thereby produce a unique wireless signal that can be read/decoded. In general, an RFID tag “reader” includes the means to transmit RF energy for activation of a RFID tag, and the means to receive RF energy produced by the RFID tag. Thus, related-art RFID readers typically employ one or more RF antennas to perform the transmission and reception functions.
In many warehouse-type environments, RFID-tagged items are carried by hand, moved about using a cart or hand truck, or moved about using conveyers, elevators, or other mechanized handling systems. RFID readers for these types of environments will incorporate a reader's antenna(s) along a travel route in order to monitor movement and/or location of RFID-tagged items. Currently, these antennas are either attached or embedded in rigid panels positioned adjacent the mechanized handling systems, or are attached or embedded in flexible panels positioned in the path of items of moving along the mechanized handling system. In either case, the antennas rarely or never come very close to the passing RFID tag. Accordingly, to assure system robustness, the antennas must generate an RF transmission with enough power to assure that the transmission reaches the RFID tag. Unfortunately, if the RFID-tagged item is sensitive to electromagnetic radiation (EM), the item could be adversely affected by the RFID reader. In terms of EM sensitive ordnance or chemicals, this situation could result in a catastrophe.